Hybrid boost converters

ABSTRACT

A method comprises configuring a power converter to operate as a boost converter, the power converter comprising a low side switch and a high side switch, during a first dead time after turning off the low side switch and before turning on the high side switch, configuring the power converter such that a current of the power converter flows through a high speed diode, and after turning on the high side switch, configuring the power converter such that the current of the power converter flows through a low forward voltage drop diode.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/566,102,entitled “Hybrid Devices for Boost Converters” and filed on Sep. 10,2019, now U.S. Pat. No. 10,938,308 issued on Mar. 2, 2021, which is acontinuation of Application No. PCT/US2018/051713, entitled “HybridBoost Converters” and filed on Sep. 19, 2018, which claims priority toUnited States Provisional Application Ser. No. 62/562,100, entitled,“Hybrid Boost Converters” and filed on Sep. 22, 2017, which applicationsare hereby incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a hybrid boost converter, and, inparticular embodiments, to a hybrid boost converter having lowerswitching and conduction losses.

BACKGROUND

Renewable energy sources include solar energy, wind power, tidal waveenergy and the like. A solar power conversion system may include aplurality of solar panels connected in series or in parallel. The outputof the solar panels may generate a variable dc voltage depending on avariety of factors such as time of day, location and sun trackingability. In order to regulate the output of the solar panels, the outputof the solar panels may be coupled to a direct current/direct current(dc/dc) converter so as to achieve a regulated output voltage at theoutput of the dc/dc converter. In addition, the solar panels may beconnected with a backup battery system through a battery charge controlapparatus. During the day, the backup battery is charged through theoutput of the solar panels. When the power utility fails or the solarpanels are an off-grid power system, the backup battery provideselectricity to the loads coupled to the solar panels.

Since the majority of applications may be designed to run on 120 voltsac power, a solar inverter is employed to convert the variable dc outputof the photovoltaic modules to a 120 volts ac power source. A pluralityof multilevel inverter topologies may be employed to achieve high poweras well as high efficiency conversion from solar energy to utilityelectricity. In particular, a high power alternating current (ac) outputcan be achieved by using a series of power semiconductor switches toconvert a plurality of low voltage dc sources to a high power ac outputby synthesizing a staircase voltage waveform.

Boost converters may be employed to generate additional voltage levelsso as to form the staircase voltage waveform of the multilevelinverters. The boost converters may be implemented by using step upcircuits such as non-isolated boost converters. A non-isolated boostconverter is formed by an input inductor, a low side switch, a blockingdiode and an output capacitor. The input inductor is coupled between aninput power source and a common node of the low side switch and theblocking diode. The output capacitor is connected to the blocking diodeand ground.

The blocking diode of the boost converter may be implemented as asilicon carbide diode or a silicon diode. The silicon carbide diode hasa high forward voltage drop, which may increase the conduction losses ofthe boost converter. The silicon diode may have poor reverse recoveryperformance, which may cause additional switching losses. It would bedesirable to have a hybrid device exhibiting good behaviors such as lowforward voltage drop and fast reverse recovery.

SUMMARY

These and other problems are generally solved or circumvented, andtechnical advantages are generally achieved, by preferred embodiments ofthe present disclosure which provide a hybrid boost converter havinglower switching and conduction losses.

In accordance with an embodiment, a method comprises configuring a powerconverter to operate as a boost converter, the power convertercomprising a low side switch and a high side switch, during a first deadtime after turning off the low side switch and before turning on thehigh side switch, configuring the power converter such that a current ofthe power converter flows through a high speed diode, and after turningon the high side switch, configuring the power converter such that thecurrent of the power converter flows through a low forward voltage dropdiode.

In accordance with another embodiment, a method comprises controlling apower converter to convert an input voltage into a regulated outputvoltage, wherein the regulated output voltage is higher than the inputvoltage and the power converter comprises a low side switch, a high sideswitch and an inductor, turning on the low side switch to store energyin the inductor, after turning off the low side switch and beforeturning on the high side switch, configuring the power converter suchthat a current of the power converter flows through a high speed diode,and turning on the high side switch to release the energy stored in theinductor, wherein after turning on the high sided switch, the current ofthe power converter flows through a low forward voltage drop diode.

In accordance with yet another embodiment, a method comprisesconfiguring a power converter to operate as a boost converter, the powerconverter comprising an inductor, a low side switch and a hybrid devicecomprising a high side switch, a high speed diode and a low forwardvoltage drop diode, after turning off the low side switch and beforeturning on the high side switch, configuring the power converter suchthat a current of the power converter flows through the high speeddiode, and after turning on the high side switch, configuring the powerconverter such that the current of the power converter flows through thelow forward voltage drop diode.

An advantage of an embodiment of the present disclosure is a hybridboost converter providing lower conduction and switching losses so as toimprove the efficiency, reliability and cost of the boost converter.

The foregoing has outlined rather broadly the features and technicaladvantages of the present disclosure in order that the detaileddescription of the disclosure that follows may be better understood.Additional features and advantages of the disclosure will be describedhereinafter which form the subject of the claims of the disclosure. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures or processes for carrying outthe same purposes of the present disclosure. It should also be realizedby those skilled in the art that such equivalent constructions do notdepart from the spirit and scope of the disclosure as set forth in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a block diagram of a boost converter in accordancewith various embodiments of the present disclosure;

FIG. 2 illustrates a schematic diagram of the boost converter shown inFIG. 1 in accordance with various embodiments of the present disclosure;

FIG. 3 illustrates the gate control signals of the switches of thehybrid boost converter shown in FIG. 2 in accordance with variousembodiments of the present disclosure; and

FIG. 4 illustrates a flow chart of a method for controlling the hybridboost converter shown in FIG. 2 in accordance with various embodimentsof the present disclosure.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the variousembodiments and are not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the presently preferred embodiments arediscussed in detail below. It should be appreciated, however, that thepresent disclosure provides many applicable inventive concepts that canbe embodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the disclosure, and do not limit the scope of the disclosure.

The present disclosure will be described with respect to preferredembodiments in a specific context, namely a hybrid boost converter. Thepresent disclosure may also be applied, however, to a variety of powerconverters. Hereinafter, various embodiments will be explained in detailwith reference to the accompanying drawings.

FIG. 1 illustrates a block diagram of a boost converter in accordancewith various embodiments of the present disclosure. The boost converter100 comprises a first switching element 112, a second switching element114, an inductor L1, an input capacitor C_(IN) and an output capacitorCo. As shown in FIG. 1 , the inductor L1 is connected to a common nodeof the first switching element 112 and the second switching element 114.The inductor L1 and the second switching element 114 are connectedbetween the input capacitor C_(IN) and the output capacitor Co. Thefirst switching element 112 is connected between the common node of theinductor L1 and the second switching element 114 and ground.

The boost converter 100 may further comprise a controller 110. As shownin FIG. 1 , the controller 110 may detect the input voltage Vin, theoutput voltage Vo, and generate two gate drive signals for controllingthe on and off of the first switching element 112 and the secondswitching element 114 respectively. The controller 110 may be a pulsewidth modulation (PWM) controller. Alternatively, the controller 110 maybe implemented as a digital controller such as a micro-controller, adigital signal processor and/or the like.

It should be noted that while the example throughout the description isbased upon a boost converter and a controller configured to generate thegate drive signals for the boost converter (e.g., the boost converter100 shown in FIG. 1 ), the boost converter 100 as well as the controller110 shown in FIG. 1 may have many variations, alternatives, andmodifications. For example, the controller 110 may detect othernecessary signals such as the input and/or output current, thedrain-to-source voltages of the boost converter 100, the temperature ofthe boost converter 100 and the like. Furthermore, there may be onededicated driver or multiple dedicated drivers coupled between thecontroller 110, and the first switching element 112 and the secondswitching element 114.

The boost converter 100 and the controller 110 illustrated herein islimited solely for the purpose of clearly illustrating the inventiveaspects of the various embodiments. The present invention is not limitedto any particular power topology.

The first switching element 112 and the second switching element 114shown in FIG. 1 may be implemented as n-type metal oxide semiconductor(NMOS) transistors. Alternatively, the switches may be implemented asother suitable controllable devices such as metal oxide semiconductorfield effect transistor (MOSFET) devices, bipolar junction transistor(BJT) devices, super junction transistor (SJT) devices, insulated gatebipolar transistor (IGBT) devices, gallium nitride (GaN) based powerdevices and/or the like.

Furthermore, at least one of the first switching element 112 and thesecond switching element 114 may be implemented as a hybrid deviceincluding a combination of a plurality of switching devices (e.g., acombination of a MOSFET device and a plurality of diodes). The detailedstructures of the plurality of switching devices will be described belowwith respect to FIG. 2 . Throughout the description, the boost converter100 may be alternatively referred to as a hybrid boost converter 100.

FIG. 2 illustrates a schematic diagram of the boost converter shown inFIG. 1 in accordance with various embodiments of the present disclosure.The hybrid boost converter 100 comprises a first switching element 112,a second switching element 114, an inductor L1, an input capacitorC_(IN) and an output capacitor Co. As shown in FIG. 2 , the inputcapacitor C_(IN) is across two output terminals (Vin+ and Vin−) of apower source Vin. The inductor L1 is connected between the inputcapacitor C_(IN) and a common node of the first switching element 112and the second switching element 114. The first switching element 112has a first terminal connected to the inductor L1 and a second terminalconnected to ground. The second switching element 114 is connectedbetween the inductor L1 and the output capacitor Co. The outputcapacitor Co is employed to suppress voltage ripples and provide asteady voltage for various loads coupled to the hybrid boost converter100.

In some embodiments, the first switching element 112 is implemented asan Insulated Gate Bipolar Transistor (IGBT) device Q1. As shown in FIG.2 , a collector of the IGBT device Q1 is connected to a common node ofthe inductor L1 and the second switching element 114. An emitter of theIGBT device Q1 is connected to ground. A gate of the IGBT device Q1 isconfigured to receive a gate drive signal from the controller 110.

As shown in FIG. 2 , a third diode D3 is connected in parallel with theIGBT device Q1. The third diode D3 is employed to provide a reverseconducting path for the hybrid boost converter 100. In other words, thethird diode D3 is an anti-parallel diode. In some embodiments, the thirddiode D3 is co-packaged with the IGBT device Q1. In alternativeembodiments, the third diode D3 is placed outside the IGBT device Q1.

The second switching element 114 comprises a switch S1, a first diodeD1, a second diode D2 and a fourth diode D4. In some embodiments, theswitch S1 is implemented as a Metal Oxide Semiconductor Field EffectTransistor (MOSFET) device. More particularly, the switch S1 is ann-type MOSFET device. Throughout the description, the switch S1 isalternatively referred to as the MOSFET device S1.

As shown in FIG. 2 , a drain of the MOSFET device S1 is connected to theinductor L1 as well as the IGBT device Q1. A source of the MOSFET deviceS1 is connected to an anode of the first diode D1. A gate of the MOSFETdevice S1 is configured to receive a gate signal from the controller110.

FIG. 2 further illustrates that the MOSFET device S1 and the first diodeD1 are connected in series to form a first conductive path between theinductor L1 to the output capacitor Co. The second diode D2 forms asecond conductive path between the inductor L1 to the output capacitorCo. As shown in FIG. 2 , the anode of the second diode D2 is connectedto the drain of the MOSFET device S1. The cathode of the second diode D2is connected to the cathode of the first diode D1. The first conductivepath and the second conductive path are connected in parallel betweenthe inductor L1 and the output capacitor Co.

In some embodiments, the fourth diode D4 is a body diode of the MOSFETdevice S1. In alternative embodiments, when the switch S1 is implementedas other suitable switching devices such as an IGBT device, a separatefreewheeling diode may be required to be connected in parallel with itscorresponding switch.

In operation, during the turn-on and turn-off transitions between theIGBT device Q1 and the MOSFET device S1, there may be two dead times.During these two dead times, both the IGBT device Q1 and the MOSFETdevice S1 are off. The second diode D2 functions as a freewheelingdiode, which provides a conductive path for the current of the hybridboost converter 100 during the dead times. In order to reduce switchinglosses during the turn-on and turn-off transitions, the second diode D2is implemented as a diode having a short reverse recovery time and a lowreverse recovery charge. The operation principle of the second diode D2will be described below with respect to FIG. 3 .

In some embodiments, the first diode D1 is implemented as is a lowforward voltage drop diode such as a Schottky diode and the like. Thesecond diode D2 is implemented as a low reverse recovery diode such as asilicon carbide diode, an ultrafast silicon diode and the like. In someembodiments, the second diode D2 has a shorter reverse recovery time anda lower reverse recovery charge than the first diode D1. The forwardvoltage drop of the second diode D2 is greater than the forward voltagedrop of the first diode D1.

In some embodiments, the output voltage of the hybrid boost converter100 is about 500 V. The voltage rating of the first diode D1 is in arange from about 600 V to about 650 V. The voltage rating of the seconddiode D2 is in a range from about 600 V to about 650 V. The voltagerating of the IGBT device Q1 is in a range from about 600 V to about 650V. The voltage rating of the MOSFET device S1 is in a range from about60 V to about 100 V.

In some embodiments, the voltage rating of the IGBT device Q1 is equalto 600 V. The voltage rating of the MOSFET device S1 is equal to 60 V.In other words, the voltage rating of the IGBT device Q1 is at least tentimes greater than the voltage rating of the MOSFET device S1.

One advantageous feature of having a combination of a high voltage IGBTdevice (e.g., 600 V IGBT device Q1) and a low voltage MOSFET device(e.g., 60 V MOSFET device S1) is the low voltage MOSFET device S1 has amuch lower turn-on resistance. The lower turn-on resistance of theMOSFET device S1 helps to improve the efficiency of the hybrid boostconverter 100.

In operation, a current may continuously flow through the inductor L1.The controller 110 generates a signal to turn off the IGBT device Q1. Inresponse to the turn-off signal applied to the gate of the IGBT deviceQ1, the IGBT device Q1 is turned off. In order to prevent the shootthrough issue, a first dead time is placed after the turn-off of theIGBT device Q1. As described above, the MOSFET device S1, the firstdiode D1 and the second diode D2 form two conductive paths connected inparallel. During the first dead time, the MOSFET device S1 remains off.The turned off MOSFET device S1 blocks the current from entering thefirst diode D1. As a result, the current of the hybrid boost converter100 completely flows through the second diode D2 during the first deadtime. Since the second diode D2 is a high speed diode (a diode having ashorter reverse recovery time and a lower reverse recovery charge), theswitching transition through the second diode D2 can reduce theswitching losses of the hybrid boost converter 100.

Likewise, when the controller 110 generates a signal to turn off theMOSFET device S1, a second dead time is placed after the turn-off of theMOSFET device S1. During the second dead time, the current completelyflows through the second diode D2. Since the second diode D2 is a highspeed diode, the switching transition through the second diode D2 canreduce the switching losses of the hybrid boost converter 100.

One advantageous feature of having a low forward voltage drop diode(e.g., first diode D1) and a low reverse recovery diode (e.g., seconddiode D1) is the low reverse recovery diode helps to reduce theswitching losses of the hybrid boost converter 100. On the other hand,the low forward voltage drop diode helps to reduce the conduction lossesof the hybrid boost converter 100.

FIG. 3 illustrates the gate control signals of the switches of thehybrid boost converter shown in FIG. 2 in accordance with variousembodiments of the present disclosure. The horizontal axis of FIG. 2represents intervals of time. There may be two vertical axes. The firstvertical axis Y1 represents the gate drive signal of the IGBT device Q1shown in FIG. 2 . The second vertical axis Y2 represents the gate drivesignal of the MOSFET device S1 shown in FIG. 2 .

As shown in FIG. 3 , the time from t0 to t4 represents one switchingcycle of the hybrid boost converter 100. The IGBT device Q1 is turned onfrom the time instant t0 to the time instant t1 as indicated by the gatedrive signal of the IGBT device Q1. During the time instant t0 to thetime instant t1, the MOSFET device S1 remains off as indicated by thegate drive signal of the MOSFET device S1.

The MOSFET device S1 is turned on from the time instant t2 to the timeinstant t3 as indicated by the gate drive signal of the MOSFET deviceS1. During the time instant t2 to the time instant t3, the IGBT deviceQ1 is off as indicated by the gate drive signal of the IGBT device Q1.

In one switching period shown in FIG. 3 , there are two dead times.During these two dead times, both the IGBT device Q1 and the MOSFETdevice S1 are off. As shown in FIG. 3 , a first dead time is from thetime instant t1 to the time instant t2. The first dead time is employedto prevent shoot-through current from flowing in the hybrid boostconverter 100 during the turn-off process of the IGBT device Q1. Asecond dead time is from the time instant t3 to the time instant t4. Thesecond dead time is employed to prevent shoot-through current fromflowing in the hybrid boost converter 100 during the turn-off process ofthe MOSFET device S1. Both the first dead time and the second dead timeare predetermined. It should be noted that the first dead time and thesecond dead time may vary depending on different applications and designneeds. In some embodiments, the switching frequency of the hybrid boostconverter 100 is about 300 KHz. The first dead time is about 50nanoseconds. The second dead time is about 50 nanoseconds.

During the first dead time and the second dead time, the current of thehybrid boost converter 100 flows through the second diode D2. The seconddiode D2 is a high speed diode, which can reduce the switching losses ofthe hybrid boost converter 100. On the other hand, during the turn-ontime of the MOSFET device S1, the current flows through the first diodeD1 having a low forward voltage drop. Such a low forward voltage drophelps to reduce the conduction losses of the hybrid boost converter 100.

FIG. 4 illustrates a flow chart of a method for controlling the hybridboost converter shown in FIG. 2 in accordance with various embodimentsof the present disclosure. This flowchart shown in FIG. 4 is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. For example, various steps illustrated in FIG. 4 maybe added, removed, replaced, rearranged and repeated.

Referring back to FIG. 2 , the hybrid boost converter 100 comprises afirst switch Q1, a second switch S1, a first diode D1 and a second diodeD2. The second switch S1 and the first diode D1 are connected in seriesbetween the inductor L1 and the output capacitor Co. The source of thesecond switch S1 is connected to the anode of the first diode D1. Thesecond switch S1 and the first diode D1 form a first conductive pathbetween the inductor L1 and the output capacitor Co. The second diode D2forms a second conductive path between the inductor L1 and the outputcapacitor Co. The first conductive path and the second conductive pathare connected in parallel between the inductor L1 and the outputcapacitor Co. In some embodiments, a conductive loss of the secondconductive path is greater than a conductive loss of the firstconductive path.

At step 402, upon receiving a turn-off signal of the first switch Q1from a feedback loop (not shown), a controller (e.g., controller 110shown in FIG. 2 ) turns off a first switch of a power converter. In someembodiments, the power converter is the hybrid boost converter 100.Referring back to FIG. 2 , the hybrid boost converter 100 comprises afirst switch Q1 implemented as an IGBT, a second switch S1 implementedas a MOSFET, a first diode D1, a second diode D2 and an inductorconnected to a common node of the first switch and a second switch.

At step 404, after a first dead time, the controller turns on the secondswitch S1. During the first dead time, the current flows through thesecond diode D2. In some embodiments, the second diode D2 is a lowreverse recovery diode such as a silicon carbide diode and the like.Such a low reverse recovery diode helps to reduce switching lossesduring the first dead time. Furthermore, after the current of the powerconverter flows through the second diode D2, the voltage stress acrossthe second switch S1 is approximately equal to zero. As such, the secondswitch S2 can achieve zero voltage switching, thereby further reducingswitching losses of the hybrid boost converter 100.

At step 406, upon receiving a turn-off signal of the second switch S1from the feedback loop, the controller turns off the second switch S1.In response to the turn-off of the second switch S1, the current movesfrom the first conductive path to the second conductive path.

At step 408, after a second dead time, the controller turns on the firstswitch. During the second dead time, the current flows through thesecond diode D2.

In some embodiments, the first dead time is about 50 nanoseconds. Thesecond dead time is about 50 nanoseconds. The first dead time and thesecond dead time given above are predetermined. The first dead timeand/or the second dead time may vary depending on different applicationsand design needs.

In some embodiments, in order to achieve zero voltage switching, thefirst dead time is longer than the second dead time. For example, thefirst dead time is about 100 nanoseconds. The second dead time is about50 nanoseconds. In other words, the first dead time is at least twice aslong as the second dead time. Such a dead time arrangement may help tofurther improve the efficiency of the hybrid boost converter 100.

Although embodiments of the present disclosure and its advantages havebeen described in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the disclosure as defined by the appendedclaims.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present disclosure, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present disclosure. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

What is claimed is:
 1. A method comprising: configuring a powerconverter to operate as a boost converter, the power convertercomprising a low side switch and a high side switch; during a first deadtime after turning off the low side switch and before turning on thehigh side switch, configuring the power converter such that a current ofthe power converter flows through a high speed diode, wherein the highspeed diode is a silicon carbide (SiC) diode; and after turning on thehigh side switch, configuring the power converter such that the currentof the power converter flows through a low forward voltage drop diode,wherein the low forward voltage drop diode is a Schottky diode.
 2. Themethod of claim 1, wherein: the high side switch is a Metal OxideSemiconductor Field Effect Transistor (MOSFET) device; and the low sideswitch is an Insulated Gate Bipolar Transistor (IGBT) device.
 3. Themethod of claim 1, wherein: the high side switch and the low forwardvoltage drop diode are connected in series between an inductor and anoutput terminal of the power converter; the high speed diode isconnected between the inductor and the output terminal of the powerconverter; and the inductor is connected between an input terminal ofthe power converter, and a common node of the low side switch and thehigh side switch.
 4. The method of claim 3, wherein: a source of thehigh side switch is connected to an anode of the low forward voltagedrop diode; a drain of the high side switch is connected to an anode ofthe high speed diode; and a cathode of the low forward voltage dropdiode is connected to a cathode of the high speed diode.
 5. The methodof claim 1, further comprising: during a second dead time after turningoff the high side switch and before turning on the low side switch,configuring the power converter such that the current of the powerconverter flows through the high speed diode.
 6. The method of claim 1,wherein: the high side switch comprises a body diode, and wherein ananode of the body diode is connected to an anode of the low forwardvoltage drop diode.
 7. The method of claim 1, further comprising:forming a first conductive path between an inductor of the powerconverter and an output terminal of the power converter through turningon the high side switch, wherein the high side switch and the lowforward voltage drop diode form the first conductive path.
 8. The methodof claim 7, further comprising: forming a second conductive path betweenthe inductor of the power converter and the output terminal of the powerconverter using the high speed diode.
 9. The method of claim 8, wherein:the second conductive path and the first conductive path are connectedin parallel.
 10. A method comprising: controlling a power converter toconvert an input voltage into a regulated output voltage, wherein theregulated output voltage is higher than the input voltage and the powerconverter comprises a low side switch, a high side switch and aninductor; turning on the low side switch to store energy in theinductor; after turning off the low side switch and before turning onthe high side switch, configuring the power converter such that acurrent of the power converter flows through a high speed diode, whereinthe high speed diode is a silicon carbide (SiC) diode; and turning onthe high side switch to release the energy stored in the inductor,wherein after turning on the high sided switch, the current of the powerconverter flows through a low forward voltage drop diode, wherein thelow forward voltage drop diode is a Schottky diode.
 11. The method ofclaim 10, wherein: the inductor and the low side switch connected inseries between an input terminal of the power converter and ground; andthe high side switch connected to a common node of the inductor and thelow side switch.
 12. The method of claim 11, wherein: the high speeddiode has an anode connected to the common node of the inductor and thelow side switch, and a cathode connected to an output terminal of thepower converter.
 13. The method of claim 11, wherein: the low forwardvoltage drop diode and the high side switch are connected in seriesbetween the common node of the inductor and the low side switch, and anoutput terminal of the power converter.
 14. The method of claim 13,wherein: a source of the high side switch is connected to an anode ofthe low forward voltage drop diode.
 15. The method of claim 10, wherein:the low side switch is an Insulated Gate Bipolar Transistor (IGBT)device; and the high side switch is a Metal Oxide Semiconductor FieldEffect Transistor (MOSFET) device.
 16. A method comprising: configuringa power converter to operate as a boost converter, the power convertercomprising an inductor, a low side switch and a hybrid device comprisinga high side switch, a high speed diode and a low forward voltage dropdiode; after turning off the low side switch and before turning on thehigh side switch, configuring the power converter such that a current ofthe power converter flows through the high speed diode, wherein the highspeed diode is a silicon carbide (SiC) diode; and after turning on thehigh side switch, configuring the power converter such that the currentof the power converter flows through the low forward voltage drop diode,wherein the low forward voltage drop diode is a Schottky diode.
 17. Themethod of claim 16, wherein: the low side switch is an Insulated GateBipolar Transistor (IGBT) device; and the high side switch is an n-typeMetal Oxide Semiconductor Field Effect Transistor (MOSFET) device. 18.The method of claim 16, wherein: the inductor and the low side switchare connected in series between an input terminal of the power converterand ground; the low forward voltage drop diode and the high side switchare connected in series between a common node of the inductor and thelow side switch, and an output terminal of the power converter; and thehigh speed diode has an anode connected to the common node of theinductor and the low side switch, and a cathode connected to the outputterminal of the power converter.